The present invention relates to the art of moveable connections, and, in particular, to connections which provide universal movement between the connected members.
It has been known in the art of universal movement swivel joints between connected members to provide interlocking members which are free to move essentially perpendicularly to each other thereby permitting the connected members to move substantially in any lateral direction relative to each other. Normally such movement is provided by attaching the two connected members to interlocking connectors which rotate at substantially a 90.degree. angle while bearing against each other.
The high degree of movement generally experienced in such joints wherein the surfaces continually bear against each other causes much wear due to friction. Consequently, it is important to provide sufficient lubrication to prevent or reduce degradation due to friction wear. Provision of lubrication to the total load-bearing surface is enhanced when there is a wide range of movement of interlocking members because the interlocking members themselves operate to spread the lubricant. However, there are also problems incurred in maintaining the appropriate amount of lubricant at the site of a joint having a wide range of movement due to difficulty in sealing the members.
In some cases, connections providing universal movement are required for mounting an actuated member or members which must swivel universally through very small angles, such as, for example, no more than about 7.degree.. Such applications incur problems different from the wide movement connections. Specifically, effective lubrication is very difficult, if not impossible, since the limited range of movement does not effect spreading of the lubricant. Consequently, the interlocking members are abraded or fretted resulting in limited part life.
Each of the different types of universal joints, whether having large angle movement or small, suffers from problems caused by friction. Thus, it is a primary object of the present invention to reduce as much as possible problems incurred as a result of friction in universal swivel connections by eliminating the friction caused by surfaces bearing against each other.